php verification code class php verification code

 /**
 * Universal verification code class img.php
 * Version: V0.1
 * bbs.it-home.org 2013/3/1
*/
 class ValidateCode {
 private $charset="abcdefghizklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"; //Random factor
 private $code; //Verification code text
 codelen= 4; //Verification code displays several words
 private $width=130; //Verification code width
 private $height=50; //Verification code height
 private $img; //Verification code resource handle
 private $font; //Specified font
 private $fontsize=20; //Specified font size
 private $fontcolor; //Random font color

 //Construction class to write font
 public function __construct(){
 $this->font =ROOT_PATH.'/font/elephant.ttf';
 }
 //Create 4 random codes
 private function createCode(){
 $_leng=strlen($this->charset);
 for($i=1 ;$icodelen;$i++){
 $this->code.=$this->charset[mt_rand(0,$_leng)];
 }
 return $this-> code;
 }

 //Create a background
 private function createBg(){
 //Create a canvas for a resource jubing
 $this->img=imagecreatetruecolor($this->width,$this->height) ;
 //Background color
 $color=imagecolorallocate($this->img,mt_rand(157,255),mt_rand(157,255),mt_rand(157,255));
 //Draw a rectangle
 imagefilledrectangle($this-> img,0,$this->height,$this->width,0,$color);
 }

 //Create font
 private function createFont(){
 $_x=($this->width / $this->codelen); //Font length
 for ($i=0;$icodelen;$i++){
 //Text color
 $color=imagecolorallocate($this-> ;img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));
 //Resource handle font size tilt font length font height font color font specific text
 imagettftext($this->img,$this- >fontsize,mt_rand(-30,30),$_x*$i+mt_rand(1,5),$this->height/1.4,$color,$this->font,$this->code [$i]);
 }
 }
 //Random lines
 private function createLine(){
 //Random lines
 for ($i=0;$i $color = imagecolorallocate( $this->img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));
 imageline($this->img,mt_rand(0,$this->width),mt_rand(0,$ this->height),mt_rand(0,$this->width),mt_rand(0,$this->height),$color);
 }
 //Random snowflakes
 for ($i=0; $i $color = imagecolorallocate($this->img,mt_rand(220,255),mt_rand(220,255),mt_rand(220,255));
 imagestring($this->img,mt_rand( 1,5),mt_rand(0,$this->width),mt_rand(0,$this->height),'*',$color);
 }
 }
 //Output background
 private function outPut (){
 //Generate header
 header('ContentType:img/png');
 //Output image
 imagepng($this->img);
 //Destroy the result set
 imagedestroy($this-> ;img);
 }
 //External output
 public function doimg(){
 //Load background
 $this->createBg();
 //Load file
 $this->createCode();
 / /Load line
 $this->createLine();
 //Load font
 $this->createFont();
 //Load background
 $this->outPut();
 }

 //Get Verification code
 public function getCode(){
 return strtolower($this->code);
 }

 }
 ?>

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